1. Field of the Invention
This invention is in the field of printed circuit boards and more particularly relates to methods for bread-boarding a variety of circuit configurations and subsequently mounting the components for a particularly desired configuration on a printed circuit board.
2. Description of the Prior Art
Printed circuit boards have come into common usage in the electronics industry for a wide variety of applications. Usually, printed circuit boards are formed from a base of insulating material, such as a phenolic resin. This conducting strips, such as those which can be formed by selectively etching away a layer of copper, are bonded to the insulating support. A pattern of mounting holes extends through the board so that various electronic components, such as resistors, transistors, diodes, jumper wires, etc., can be mounted on one surface of the board by inserting their leads through the board. Thin conducting strips are typically present on both surfaces of the board, although some boards have such strips on one side only. The leads of the electronic components extend through the printed circuit board and are joined in electrical contact with the thin conducting strips by soldering them thereto.
Often, it is desirable to test a number of experimental circuits by repeatedly inserting and removing a variety of electronic components from a circuit board which provides for interconnection between the components. This procedure is known as breadboarding and is designed to provide for the rapid interconnection, testing and removal of various electronic components until a final circuit is decided upon.
There are, of course, many known systems for breadboarding electronic circuits. Generally, all of these systems can be divided into two main categories: those that require soldering to make interconnections between components, and those in which interconnections are made in a mechanical fashion only.
An example of a breadboard system which requires soldering is described in U.S. Pat. No. 3,496,419 to Sakellakis. In this system, a circuit board is provided with conductive pads corresponding to component lead patterns to which component leads are tack soldered. Interconnections are made by soldering jumper wires from pad to pad. Since a large number of components are frequently added and subsequently removed in the experimentation leading up to the final design of the circuit, however, the requirement for soldering and desoldering each interconnection is inordinately time consuming and a distinct disadvantage.
Mechanical breadboarding systems overcome this problem and provide for a quicker means for inserting and removing components from the experimental circuits. These mechanical systems, however, also have significant drawbacks. For example, many systems require the insertion of various types of terminals into holes in a prepunched board and these terminals are usually large compared to the size of the components connected which does not allow for a compact circuit layout. Also, the use of such terminals can result in loose connections making the circuit difficult to test and unreliable for use after the breadboarding phase is completed.
Solderless breadboard sockets overcome some of the problems found in other mechanical systems. With solderless breadboard sockets, connections are made by inserting component leads into rows and columns of spring-loaded connector strips imbedded in a plastic socket. The socket provides insulation between connector strips and a matrix of holes over the strips which serves to guide the component leads into the spring-loaded fingers of the connector strips. The rows and columns of connector strips are closely spaced in a relatively low profile compared to other mechanical terminals. Therefore, solderless breadboard sockets provide a means for creating a relatively compact and uncluttered breadboard version of a circuit.
Although components can be connected and disconnected to a solderless breadboard socket quickly and simply, and circuits can be laid out with a component density approaching that of a custom designed printed circuit board, one of the major problems of other mechanical systems remains. That is, the mechanical means of making interconnections is not reliable enough to be used beyond the breadboard stage. Therefore, the final circuit configuration must be removed from the solderless breadboard socket, one component at a time, and transferred to another board, usually a printed circuit board. Each component must be then connected to the printed circuit board in a permanent fashion, usually by soldering. As can be appreciated, this transfer from a solderless breadboard socket to a printed circuit board is a tedious and time consuming process.
Printed circuit boards have been manufactured with a drilled hole pattern and circuit pattern stated to match the patterns of a solderless breadboard socket. In practice, the patterns are sometimes found not to match, and in any event, such boards are used by placing them beside a solderless breadboard socket and transferring components one-by-one. This is still tedious and time consuming.